Molecular biology research methods evolve through the development of the technologies used for carrying these methods out. Due to technical difficulties it may not be possible to analyze a large number of genes using traditional methods. Deoxyribonucleic acid (DNA) microarray is one such technology which enables the researchers to investigate and address issues which were once thought to be non-traceable. One may analyze the expression of many genes in a single reaction quickly and in an efficient manner. DNA microarray technology has empowered the scientific community to understand the fundamental aspects underlining the growth and development of life as well as to explore the genetic causes of anomalies occurring in the functioning of the human body.
A typical microarray experiment involves the hybridization of an mRNA molecule to the DNA template from which it is originated. Many DNA samples are used to construct an array. The amount of mRNA bound on the array indicates the expression level of the various genes. This number may run in thousands. All the data may be collected and a profile may be generated for gene expression in the cell.
In addition to that the polymerase chain reaction (PCR) is a technique widely used in molecular biology. A DNA polymerase is used to amplify a piece of DNA by an in vitro enzymatic replication. As PCR progresses, the DNA generated is used as a template for replication. This sets in motion a chain reaction in which the DNA template is exponentially amplified. Furthermore, real-time PCR (rtPCR) or quantitative PCR is used to measure the quantity of a PCR product preferably in real-time. rtPCR is the method of choice to quantitatively measure starting amounts of for example DNA. Real-time PCR is commonly used to determine whether for example a DNA sequence is present in a sample and the number of its copies in the sample. Real-time PCR methods use fluorescent dies or fluorophore containing DNA probes to measure the amount of amplified product in real-time.
An alternative to real-time PCR, with a potentially higher multiplexing grade, is real-time array PCR where the amplicons during at least one of the PCR cycles are hybridized on an array containing regions where amplicons can specifically hybridize to capture probes with a sequence matching part of the sequence of the amplicons.
An essential requirement for real-time array PCR is a cartridge that can withstand the thermally induced stress during the temperature cycling, in which different varying temperature fields are generated by a thermocycler, processing a desired PCR protocol.